Unexpected java.util.Scanner behaviour

Question

Is it just me or do others find the following behaviour strange? It seems that in order to break out of the loop in the following, it's necessary to enter some character(s) unparseable as a double. Hitting return won't cause it to break:
     public static void scanInts(String[] args) {
          Scanner scanner = null;
          List<Double> coefficients = new ArrayList<Double>();
          double x = Double.NaN;
          try {
               scanner = new Scanner(System.in);
               while(scanner.hasNextDouble()) {
                    double d = scanner.nextDouble();
                    System.out.println("double=" + d);
                    coefficients.add(d);
               System.out.println("Now out of loop");
          finally {
               System.out.println(coefficients);
               scanner.close();
     }

Answer 1

I don't think it's strange; Scanner is supposed to ignore extra whitespace and line breaks are whitespace. You can change this behaviour by setting the delimiter to something else, like:scanner.useDelimiter("[ ]*");